Eastmanosteus Temporal range: | |
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E. calliaspis skull on display at the American Museum of Natural History in New York City | |
Artist's reconstruction of E. calliaspis | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | † Placodermi |
Order: | † Arthrodira |
Suborder: | † Brachythoraci |
Clade: | † Eubrachythoraci |
Clade: | † Pachyosteomorphi |
Superfamily: | † Dunkleosteoidea |
Family: | † Dunkleosteidae |
Genus: | † Eastmanosteus Obruchev, 1964 |
Type species | |
Dinichthys pustulosus (Eastman, 1897) | |
Species | |
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Eastmanosteus ("Eastman's bone") is a fossil genus of dunkleosteid placoderms. It was closely related to the giant Dunkleosteus , but differed from that genus in size, in possessing a distinctive tuberculated bone ornament, a differently shaped nuchal plate and a more zig-zagging course of the sutures of the skull roof. [1]
Species of Eastmanosteus had powerful jaws with sharp cutting edges and were likely active predators. Fossils have been found in many parts of the world in marine sediments dating from the Middle to Late Devonian. They were medium-to-large fish, with specimens E. pustulosus and E. licharevi approaching a total length of 3 metres. Complete exoskeletons with soft-tissue traces of E. calliaspis from Australia make this one of the best known dunkleosteids.
Eastmanosteus and its relative Dunkleosteus belong to the family Dunkleosteidae. The phylogeny of Eastmanosteus can be shown in the cladogram below: [2]
Dunkleosteoidea |
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Alternatively, the subsequent 2016 Zhu et al. study using a larger morphological dataset recovered Panxiosteidae well outside of Dunkleosteoidea, leaving the status of Dunkleosteidae as a clade grouping separate from Dunkleosteoidea in doubt, as shown in the cladogram below: [3]
Dunkleosteoidea |
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From the Frasnian Gogo Formation of northwestern Western Australia. This is the best known member of the genus with many articulated skulls and trunk armours in museum collections. [4] Evidence of muscle fibres, circulatory structures and nerve tissue have been preserved representing some of the oldest known gnathostome soft tissue. [5] The largest known skull is 272mm in length suggesting a total body length of roughly 1.5m. It was one of the largest fish in the Gogo assemblage. [6] A reexamination of the family Dunkleosteidae posits the Late Emsian Xiangshuiosteus as E. calliaspis' sister taxon, and further implicates that E. calliaspis differs enough from other members of this genus to merit placement with its own genus. [2]
A poorly known species from Russia, originally described from an isolated nuchal plate from the Frasnian of Timman with additional material from the Famennian of Lipetsk. [4]
A medium-sized species from the Eifelian of south-central Manitoba, Canada. One of the earliest and most completely known members of the genus. [7]
Based on a single almost complete head shield from the Late Devonian of New York State, US. Has previously been assigned to Dinichthys and Dunkleosteus. [4]
This is the type species and was originally placed in the genus Dinichthys. It was a large and widely distributed form, with fossil material from the Middle-Late Devonian of the USA (Wisconsin, Iowa, Michigan, New York State) and the Frasnian of Poland. [4]
Originally assigned to Dunkleosteus. From the Middle Devonian of Yunnan Province, China. [1]
An undescribed species based on relatively well preserved material from the Frasnian of Kerman, East Iran. [4]
Many other species have been included within this genus based on material from Russia, Morocco, and the United States. Most of these are either indeterminate dinichthyids or are now placed in different genera. [4]
Dunkleosteus is an extinct genus of large arthrodire fish that existed during the Late Devonian period, about 382–358 million years ago. It consists of ten species, some of which are among the largest placoderms to have ever lived: D. terrelli, D. belgicus, D. denisoni, D. marsaisi, D. magnificus, D. missouriensis, D. newberryi, D. amblyodoratus, and D. raveri, and the largest and most well known species is D. terrelli. Since body shape is not known, various methods of estimation put the living total length of the largest known specimen between 4.1 to 10 m long and weigh around 1–4 t. Dunkleosteus could quickly open and close its jaw, like modern-day suction feeders, and had a bite force of 4,414–6,170 N at the tip and 5,363–7,495 N at the blade edge. Numerous fossils of the various species have been found in North America, Poland, Belgium, and Morocco. Dunkleosteus was a pelagic fish inhabiting open waters, and an apex predator of its ecosystem.
Dinichthys is an extinct monospecific genus of large marine arthrodire placoderm from the Late Devonian measuring around 3 metres (9.8 ft) long. Fossils were recovered from the Ohio Shale Formation along the Olentangy River in Delaware County, Ohio.
Dunkleosteidae is an extinct family of arthrodire placoderms that lived during the Devonian period. The gigantic apex predator Dunkleosteus terrelli is the best known member of this group.
Rolfosteus is an extinct monospecific genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period, found at the Gogo Formation of Western Australia.
Plourdosteus is an extinct genus of placoderm arthrodire which was relatively widespread in Euramerica during the Givetian to Frasnian ages of the Devonian. It was a small placoderm, with P. canadensis measuring 37.5–51.4 cm (14.8–20.2 in) long.
Mcnamaraspis is an extinct monospecific genus of arthrodire placoderm that inhabited the ancient reef system of north Western Australia during the Frasnian epoch of the Late Devonian period. The type specimen was found and described by John A. Long from the Gogo Formation near Fitzroy Crossing. This fossil fish showed new anatomical features in arthrodires, like the well-preserved annular (ring-shaped) cartilages of the snout, previously inferred to be present by Erik Stensiö of Sweden. It is occasionally referred to as "The Gogo Fish" after the locale the holotype was excavated from.
Aspinothoracidi is a clade of placoderms, extinct armored fish most diverse during the Devonian. The gigantic apex predator Dinichthys, is the best-known member of this group. Many other genera, such as the infamous Dunkleosteus, were previously thought to be close relatives of Dinichthys and were grouped together in the family Dinichthyidae, though more recent studies have restricted that family to only its type species.
Fallacosteus is an extinct monospecific genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period, found at the Gogo Formation of Kimberley, Western Australia. As with almost all other camuropiscids, F. turneri had an elongated snout that may have enhanced its hydrodynamic streamlining.
Camuropiscis is an extinct genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period, found at the Gogo Formation of Kimberley, Western Australia. The species of Camuropiscis had a flattened, elongated snout that may have aided in enhancing its hydrodynamic streamlining.
Xiangshuiosteus wui is an extinct monospecific genus of brachythoracid arthrodire placoderm from the Late Emsian stage of the Early Devonian epoch, discovered in Wuding County of Yunnan province, China. It has recently been reassessed as a dunkleosteid.
Dunkleosteoidea is an extinct superfamily of arthrodire placoderms that lived during the Devonian period. The gigantic apex predator Dunkleosteus terrelli is the best known member of this group.
Eubrachythoraci is an extinct clade of arthrodire placoderms within the suborder Brachythoraci, armored fish most diverse during the Devonian. Most are considered to be pelagic long-distance swimmers, leading to their widespread distribution beginning from at least the Middle Devonian period.
Pachyosteomorphi is an extinct clade of arthrodire placoderms within the Eubrachythoraci, armored fish most diverse during the Devonian. Most are considered to be pelagic long-distance swimmers, leading to their widespread distribution beginning from at least the Middle Devonian period.
Compagopiscis is an extinct genus of placoderm known from the Gogo Formation. It lived in the Upper Devonian of Western Australia. The genus is monotypic, with its only species being Compagopiscis croucheri.
Golshanichthys is an extinct monospecific genus of dunkleosteid from the Late Devonian: Frasnian stage from Kerman, Iran.
Westralichthys is an extinct monospecific genus of dunkleosteoid from the Late Devonian: Middle Famennian stage from Western Australia. It is estimated to be 3 meters (9.8 ft) long.
Panxiosteidae is an extinct family of arthrodire placoderms that lived during the Devonian period.
Panxiosteus is an extinct monospecific genus of placoderm arthrodire from the Middle Devonian: Givetian stage of Yunnan province, China.
Janiosteus is an extinct monospecific genus of placoderm arthrodire from the Middle Devonian: Late Givetian stage found in Timan, Russia.
Torosteus is an extinct genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period. Fossils are found in the Kimberley region of Australia.